Patients who present with SCCHN for whom surgery is the recommended treatment will, assuming they fulfill the eligibility criteria, be block randomised into a two-group, double-blind randomised controlled trial. One group will receive IMPACT, the other an iso-caloric, iso-nitrogenous control feed for 5 days pre and 7 days post-operatively. In both groups patients will be fed enterally. The feeds will be prepared in identical bottles to facilitate blinding. Primary outcome measures include major systemic infection, whilst secondary outcome measures include local infection and length of hospital stay. Follow-up will be for 30 days postsurgery.